3.8  check-box%

Implements: control<%>

A check box is a labeled box which is either checked or unchecked.

Whenever a check box is clicked by the user, the check box's value is toggled and its callback procedure is invoked. A callback procedure is provided as an initialization argument when each check box is created.

• (new check-box% (label _) (parent _) [(callback _)] [(style _)] [(value _)] [(font _)] [(enabled _)] [(vert-margin _)] [(horiz-margin _)] [(min-width _)] [(min-height _)] [(stretchable-width _)] [(stretchable-height _)]) -> check-box% object
     label : string (up to 200 characters) or bitmap% object
     parent : frame%, dialog%, panel%, or pane% object
     callback = (lambda (c e) (void)) : procedure of two arguments: a check-box% object and a control-event% object
     style = null : list of symbols in '(deleted)
   value = #f : boolean
     font = normal-control-font : font% object
     enabled = #t : boolean
     vert-margin = 2 : exact integer in [0, 1000]
     horiz-margin = 2 : exact integer in [0, 1000]
     min-width = 0 : exact integer in [0, 10000]
     min-height = 0 : exact integer in [0, 10000]
     stretchable-width = #f : boolean
     stretchable-height = #f : boolean

  Creates a check box with a string or bitmap label. If label is a bitmap, then the bitmap must be valid (see ok? in bitmap%) and not installed in a bitmap-dc% object; otherwise, an exn:fail:contract exception is raised. If the bitmap has a mask (see get-loaded-mask in bitmap%) that is the same size as the bitmap, then the mask is used for the label; furthermore, in contrast to the limitations of draw-bitmap in dc<%>, non-monochrome label masks work consistently on all platforms.

  If an ampersand (``&'') occurs in label (when label is a string), it is specially parsed; under Windows and X, the character following an ampersand is underlined in the displayed control to indicate a keyboard mnemonic. (Under Mac OS X, mnemonic underlines are not shown.) The underlined mnemonic character must be a letter or a digit. The user can effectively click the check box by typing the mnemonic when the control's top-level-window contains the keyboard focus. The user must also hold down the Meta or Alt key if the keyboard focus is currently in a control that handles normal alphanumeric input. The ampersand itself is removed from label before it is displayed for the control; a double-ampersand in label is converted to a single ampersand (with no mnemonic underlining). Under Mac OS X, a parenthesized mnemonic character is removed (along with any surrounding space) before the label is displayed, since a parenthesized mnemonic is often used for non-Roman languages. Finally, any text after a tab character is removed on all platforms. Mnemonic keyboard events are handled by on-traverse-char (but not under Mac OS X).

  The callback procedure is called (with the event type 'check) whenever the user clicks the check box.

  If style includes 'deleted, then the check box is created as hidden, and it does not affect its parent's geometry; the check box can be made active later by calling parent's add-child method.

  If value is true, it is passed to set-value so that the box is initially checked.

  The font argument determines the font for the control. For information about the enabled argument, see window<%>. For information about the horiz-margin and vert-margin arguments, see subarea<%>. For information about the min-width, min-height, stretchable-width, and stretchable-height arguments, see area<%>.

  
  

Methods
    get-value
    set-label
    set-value

All Methods
    accept-drop-files from window<%>
    client->screen from window<%>
    command from control<%>
    enable from window<%>
    focus from window<%>
    get-client-size from window<%>
    get-cursor from window<%>
    get-font from control<%>
    get-graphical-min-size from area<%>
    get-handle from window<%>
    get-height from window<%>
    get-label from window<%>
    get-parent from area<%>
    get-plain-label from window<%>
    get-size from window<%>
    get-top-level-window from area<%>
    get-value from check-box%
    get-width from window<%>
    get-x from window<%>
    get-y from window<%>
    has-focus? from window<%>
    horiz-margin from subarea<%>
    is-enabled? from window<%>
    is-shown? from window<%>
    min-height from area<%>
    min-width from area<%>
    on-drop-file from window<%>
    on-focus from window<%>
    on-move from window<%>
    on-size from window<%>
    on-subwindow-char from window<%>
    on-subwindow-event from window<%>
    on-superwindow-enable from window<%>
    on-superwindow-show from window<%>
    popup-menu from window<%>
    refresh from window<%>
    screen->client from window<%>
    set-cursor from window<%>
    set-label from check-box%
        overrides set-label from window<%>
    set-value from check-box%
    show from window<%>
    stretchable-height from area<%>
    stretchable-width from area<%>
    vert-margin from subarea<%>